Providing structured query language (SQL) access for distributed file systems (DFS) such as HADOOP® DFS is becoming more common in big-data management. Currently, SQL access is provided by building DFS-based SQL engines, loading data into relational database management systems (DBMS's) from DFS's, and storing relation tables in DFS's as external tables. In this case, the SQL engines read data from a DFS using table-scan. Further, a DFS file is an external data source that cannot provide a locality hint for parallelizing query execution. Accordingly, a master server is typically employed for gathering data source information and scheduling parallel data retrieval. HADOOP® is a registered trademark of Apache Software Foundation, which is headquartered in Forest Hill, Md.